Green fluorescent organic light-emitting device with external quantum efficiency of nearly 10%

Abstract

Green fluorescent organic light-emitting device (OLED) exhibiting a high external quantum efficiency of nearly 10% has been developed. The OLED consists of simple three organic layers, using NPB, 0.8% C545T doped TPBA, and DBzA as a hole-transporting layer, an emitting layer, and an electron-transporting layer, respectively, [fluorocarbon coated indium tin oxide/NPB (60 nm)/08% C545T doped TPBA (40 nm)/DBzA (20 nm)/LiF (1 nm/Al], where NPB is $4,4^{\prime }$ -bis ($N$ -phenyl-1-naphthylamino)biphenyl, C545T is 10-(2-benzothiazolyl)-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-$1H,5H,11H$ -benzo$\left[l\right]$ pyrano[6 7 8-$ij$ ]quinolizin-11-one, TPBA is $9,9^{\prime },10,{10}^{\prime }$ -tetraphenyl-$2,2^{\prime }$ -bianthracene, and DBzA is 9,10-bis[4-(6-methylbenzothiazol-2-yl)phenyl]anthracene. The high external quantum efficiency is maintained in the wide range of current density of $2–100$ $\mathrm{mA}∕{\mathrm{cm}}^2$ . The current efficiency and power efficiency of the OLED are also very high, 29.8 cd/A and 26.2 lm/W, respectively, at a current density of 20 mA/${\mathrm{cm}}^2$ . The OLED is promising for practical use with high color purity with Commission Internationale de L’Eclairage coordinates of (0.24, 0.62) and long half-lifetime of $71\mathrm{h}$ at a current density of $80\mathrm{mA}∕{\mathrm{cm}}^2$ (initial luminance of $23900\mathrm{cd}∕{\mathrm{m}}^2$ ).